07
Jan
EPA Responds to Call for Chlorpyrifos Ban with New Risk Calculations and Continued Use
(Beyond Pesticides, January 7, 2015) On Monday, the U.S. Environmental Protection Agency (EPA) released a revised human health assessment for the insecticide, chlorpyrifos, which finds risks to workers who mix, load and apply chlorpyrifos, and that the chemical has the potential to pose risks to drinking water in small watersheds. The assessment also notes that EPA will retain the 10X (10-fold) safety factor to protect children from all routes of exposures. EPA’s latest finding confirms long-standing scientific data that has documented chlorpyrifos’ toxicity to humans and environmental contamination. However, despite these findings, EPA proposes to place additional restrictions on chlorpyrifos’ use, instead of a widespread ban.
This latest assessment updates the June 2011 preliminary human health risk assessment, which was widely criticized by environmental and farmworker groups. EPA is releasing this assessment based 
on new information received since 2011, including public comments. The assessment is, in part, in response to a petition submitted by Natural Resources Defense Council (NRDC) and Pesticide Action Network (PAN) in 2007, which called on the agency to ban all uses of the insecticide. In 2000, EPA orchestrated a voluntary cancellation with the manufacturer Dow AgroSciences of most residential uses of chlorpyrifos to limit children’s exposure, while most agricultural uses remain in use. Since then advocates across the country have called on EPA to ban the chemical, citing its potent toxicity. In 2010, over 13,000 organizations and individuals submitted a letter to EPA calling for a ban. In 2012, EPA imposed “no-spray” buffer zones around public spaces, including recreational areas, schools and homes to reduce bystander exposure risks. But in spite of these restrictions, chlorpyrifos still poses risks to human and environmental health because the agency refuses to step up and ban the chemical.
Children
In the 2011 assessment, EPA proposed to reduce the Food Quality Protection Act (FQPA) safety factor for certain exposures. This safety factor is an additional “margin of safety” put in place to protect vulnerable populations, especially children, from pesticide exposures. Beyond Pesticides and others in comments challenged EPA’s reduction of the safety factor, given that the human health risk, especially to children, is associated with significant neurodevelopmental effects. In response to this, recent neurotoxicity data, and feedback from a 2012 Scientific Advisory Panel- that found chlorpyrifos exposures during certain developmental periods produced significant and long-term effects, EPA now states that it will retain the FQPA 10X safety factor for “infants, children, youths, and women of childbearing age for all exposure scenarios.”
Farmworkers
According to EPA, this latest assessment shows “some risks to workers who mix, load and apply chlorpyrifos pesticide products.” The agency states that “’additional restrictions may be necessary to ensure that workers who use or work around areas treated with chlorpyrifos are protected…” The agency notes that it will now begin discussions to put yet more restrictions in place to reduce these risks. However, anything short of a ban on chlorpyrifos will continue to place farmworkers at risk from chlorpyrifos, especially workers and their families living in the vicinity of treated fields. Dermal and oral exposures to aerial spraying and inhalation exposures to ground spraying result in elevated exposures. EPA’s 2013 volatilization assessment confirms that vapor phase chlorpyrifos may be emitted from treated fields at levels resulting in exposure to children and others who live, work, attend school, or otherwise spend time nearby. EPA reports that for some scenarios protective equipment can mitigate risks, but risks remain for over 126 exposure scenarios that cannot mitigated with protective equipment, which supports previous assertions that EPA’s assessments continue to show that chlorpyrifos uses cannot be adequately mitigated by protective equipment.
Drinking Water
Additionally, EPA finds that when used in large amounts, “chlorpyrifos has the potential to pose risks in limited geographic areas when drinking water from small watersheds.” EPA confirms previous findings that chlorpyrifos’ metabolite, chlorpyrifos oxon, can pose a threat to drinking water. Little environmental data exists for this metabolite, but it is more toxic than its parent and can persist through water treatment and remain in drinking water. The agency indicates that work will be carried out to “pinpoint community drinking water systems where exposure to chlorpyrifos oxon as a result of chlorpyrifos applications may pose an exposure concern.”
Chlorpyrifos is an organophosphate insecticide that is known to be neurotoxic. It is a cholinesterase inhibitor, which means that it can bind irreversibly to acetylcholine esterase (AchE), an essential enzyme for normal nerve impulse transmission in the brain, inactivating the enzyme. Studies have documented that exposure to even low levels of organophosphates like chlorpyrifos during pregnancy can impair learning, change brain function and alter thyroid levels of offspring into adulthood. The evidence of the neurotoxic dangers associated with chlorpyrifos’ exposure is extensive and consistent. One study from the University of California, Berkeley, which examined families in the intensive agricultural region of Salinas Valley, California, found that IQ levels for children with the most organophosphate exposure were a full seven IQ points lower than those with the lowest exposure levels. The Berkeley team also found that every tenfold increase in measures of organophosphates detected during a mother’s pregnancy corresponded to a 5.5 point drop in overall IQ scores in the 7-year-olds. Researchers from Mount Sinai School of Medicine also found that prenatal exposure to organophosphates is negatively associated with cognitive development, particularly perceptual reasoning, with evidence of effects beginning at 12 months and continuing through early childhood. Visit Pesticide Induced-Disease Database (PIDD).
Last September, the California Department of Pesticide Regulation announced steps for tighter oversight of applications of chlorpyrifos in the state. However, restrictions do not go far enough. PAN and NRDC, as a follow up to their 2007 petition, filed another suit asking the court to find that EPA has “unreasonably delayed fulfilling its legal obligations” and that the agency respond to the 2007 petition by issuing a final decision by the end of 2014.
Once again, when it comes to chlorpyrifos, EPA prefers to simply mitigate risk. By focusing on risk reduction strategies to come up with “acceptable,” but unnecessary, rates of illness across the population, EPA continues to underestimate the impact of the chemical’s continued widespread use in agriculture. Chlorpyrifos is highly neurotoxic and a frequent water contaminant and long range contaminant, exposing communities and contaminating areas far from where it was applied. Residues in food and water continue to put public health at risk. Beyond Pesticides has long advocated for an enlightened policy approach to proposed or continued toxic chemical use, in an age where the adverse effects have been widely and increasingly documented, is to first ask whether there is a less toxic way of achieving the toxic chemical’s intended purpose. Simply, “Is there another practice that would make the substance unnecessary?” This approach does not preclude and should demand the prohibition of high hazard chemical use, those chemicals that are simply too dangerous.
Hazards associated with toxic pesticides, such as chlorpyrifos, are unnecessary, and therefore unacceptable, given the viability of organic agricultural practices that integral to a growing $35 billion market. See Beyond Pesticides’ organic program page.
This human health assessment will be open for a 60 day comment period once published in the Federal Register.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.
Source: EPA News Release
